There are many systems known in the prior art for constructing prefabricated railings and the like. These constructions generally comprise a sub rail which supports a top, or finishing rail, vertical bars or pickets which are secured to the sub rail, and brackets which secure the sub rail to walls or posts. Although the basic design consideration for these railing systems is to minimize the amount of field preparation for the various parts, experience has shown that extensive field work is often required. For example, this is often the case when the prefabricated parts which are orthogonal must be adapted to walls which are not plumb or which are canted.
It is often found that the actual wall spacing varies from the nominal design dimensions, and thus from the dimensions of the precut railing parts. In such case the railing must be modified at the job site to accommodate the actual wall spacing. Often spacer blocks must be used, or the mounting bracket and sub rail must be re-drilled to provide the correct spacing. This field modification is expensive and time consuming.